1. Field of the Invention
The present invention relates to a non-contact transport apparatus capable of maintaining and transporting a workpiece in a non-contact state by a pressure fluid.
2. Description of the Related Art
Heretofore, non-contact transport apparatuses have been known for handling the transport of semiconductor wafers, and which are capable of transporting workpieces formed as sheet shaped parts, making up liquid crystal and plasma display devices, in a non-contact manner utilizing the Bernoulli effect generated by the flow of a gas.
Such a non-contact transport device, for example, as disclosed in Japanese Laid-Open Patent Publication No. 2002-64130, includes a recess wherein an inner circumferential surface thereof has a cylindrical shape, and a flat surface is formed on an opening side of the recess facing the workpiece, together with a fluid passage for ejecting a supplied fluid to the interior of the recess from jetting holes facing the inner circumferential surface of the recess. In addition, by causing a flow of air current at high speeds between the flat surface and the workpiece by means of air supplied from a fluid introduction port, a negative pressure is generated by the Bernoulli effect and the workpiece is lifted, whereby the workpiece can be transported by means of positive pressure air currents that flow between the flat surface and the workpiece, while maintaining a non-contact state therebetween.
Further, in this type of non-contact transport apparatus, the supplied amount (pressure) of air is constant, wherein workpieces having various weights and sizes respectively are transported. Accordingly, there has been a demand to be able to maintain and transport even larger and heavier workpieces by increasing the force at which workpieces can be held. At the same time, there has also been a demand to stably maintain and transport thin lightweight workpieces. More specifically, a non-contact transport apparatus has been desired, which is capable of maintaining and transporting even more various types of workpieces, while enlarging the range at which the workpieces can be maintained, with respect to a fixed supply amount (pressure) of air.